Stay-bolt for boilers.



B.. E. D. STAFFORD & E. I. DODDS.

STAY BOLT FOR BOILERS.

IIIIIIIIIIIIIIIIIIIII 1914.

l ,l 8,855. f Patented June 27, 19m.

A rgizmunlun, f

IINITE STATES PATENT FFIQE.

BENJAMIN E. D. STAFFORD AND ETI-IAN I. DODDS, OF PITTSBURGH,PENNSYLVANIA, ASSIGNORS TO FLANNERY BOLT COI/IPANY, OF PITTSBURGH,PENNSYLVANIA.

STAY-BOLT FOR BOITIERS.

messes.

Application filed November 24, 1914.

T0 all whom 'it may concern Be it known that we, BENJAMIN E. D. STAFFORDand Eri-IAN I. Donne, citizens of the United States, and residents ofPitts burgh, in the county of Allegheny and State of Pennsylvania, haveinvented certain new and useful Improvements in Stay-Bolts for Boilers;and we do hereby declare the following to be a full, clear, and exactdescriptien of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

Our invention relates to an improvement in flexible stay bolts forboilers,the object being to provide a yielding coupling for the outerend of the bolt, whereby the latter' will be flexibly connected to theouter sheet so that it may be free to follow the movements of the lirebox sheet without unduly straining eitherl of the sheets to which it isconnected.

I/Vith this object in view our invention consists in a two part bushingadapted to be secured to the outer sheet of the boiler the inner memberof said bushing having an internal seat for the head of a stay bolt, anda yielding member interposed between the head of the bolt and the innerface of the outer member' of the bushing whereby the said head will beyieldingly held against its seat.

In the accompanying drawings, Figures l to 5 inclusive are views insection of various forms embodying our invention. i

l represents a bushing externally threaded at one end .tor itsattachment to the outer sheet of a boiler, and also threaded at itsouter end for the attachment ot the cap Q. The bushing or sleeve l isprovided internally with the curved seat 3 on which the 'rounded head 4oi" the bolt rests, the opposite end ot' the bolt being secured to theinner sheet oi the boiler in the well known manner.

Located between the inner Jface of the cap, 2, and outer end of the headl of the bolt is a resilient or spring device designed to normally holdthe bolt head on its seat, but which may yield or give so as to permitthe bolt to move longitudinally, to accommodate itself to the movementsof the inner sheet of the boiler to which the bolt is attached.

In the construction shown in Fig. l, the yielding member 6 is of springmetal ap- Speccaton of Letters Patent.

Patented June 27, 1916.

serial No. 873,795.

The head o'lf the bolt is VHat with a central concave recess to receiveone end of the yielding member, 6, and the inner face of the cap 2 issimilarly recessed to receive the other end oiC member (5, sutiicientspace being lett between the end of the head of the bolt and the inner'face ot' the cap, to accommodate all longitudinal movements to `whichthe bolt may ne subjected. The bolt head and a portion oi1 the boltadjacent the head, is provided with atell-tale bore, and the springmember G is provided with holes 8, which communicate respectively withthe tell-tale bore in the bolt, and the central opening 9 in the cap 2,to permit steam or water to escape, in the event the bolt should bebroken. The spring member G makes a tight joint with the cap and boltand is preferably compressed by the cap as the latter is secured inplace, so that there never can be any leakage ot' steam around the headoir' the bolt and through the tell-tale hole 9 in the cap.

In Fig. 2 the yielding member (in made of spring metal is cylindrical inform and bellows shaped as shown. Its outer end is concave to receivethe convex inner face et' the cap, and its inner end concave to receivethe convex outer end of the head of the bolt. It also has a central boreor passage way which connects the tell tale in the bolt with the opening9 in the ca'p. This bellows shaped or spring member, instead oit beingcyliinlrical as in Fig. 2 may be spherical as in Fig. 3. In the latterconstruction we have shown the spring men'lbcr G" resting within aconcave scat in the cap, and the head oi the bolt provided with a raisedconcave member l0, resting in a concave seat in the spring member, butit is clearly evident that the head of the bolt may have a concave seat,as in the cap, for the spring member, or the cap may have a convex seatto rest in a eoncavity in the spring member. It is also provided with a'central bore connecting the tell-tale in the bolt with the hole 9 in thecap.

In the construction shown in Fig. 4C the spring member 6C comprises asemi-spherical portion having a hollow threaded shank 1]. screwed to thehead oit' the bolt. In Fig. 4,

we have shown it screwed into a recess in the head of the bolt, and inFig. 5 we have shown the shank internally threaded to receive theinternally threaded head of the bolt 5. In the construction shown inFig. 4L the rounded bolt head rests on the curved seat in the bushing,whereas in F ig. 5, the spring member constitutes the head ol the boltand rests on the curved seat in the bushing.

In both of the constructions, the spring member is substantially ofbellows form so as to permit it to yield or give under the ini'luence oflongitudinal stresses imparted to the bolt.

If desired the cap 2 oit' the bushing may be provided with an adjustingscrew Il adapted to bear against the spring member whereby the same maybe put under compression either at the start or in the event thereshould be any weakening ot' the spring a'lter usage. This screw may havea tell-tale bore l5.

In all ol the forms shown, the spring member tends to holdthe bolt headfirmly on its seat in the bushing, but is free to give or yield topermit of longitudinal movement of the bolt, and when under compressionby the bolt, 'lorms a steam tight joint with the latter and also withthe cap so as to prevent the escape of steam or water. They also leavethe bolt free to have universal movement on its seat 3 in the bushing,and also free to respond to all lateral movements of the inner sheet,without undulyA straining it, or the outer sheet to which the bushing issecured.

It is evident that many slight changes might be resorted to in therelative arrangement of parts shown and described without departing fromthe spirit and scope' of our invention. Hence we would have itunderstood that we do not wish to confine ourselves to the exactconstruction and arrangement of parts shown and described, except asrequired by the scope of the appended claims.

Having fully described our invention what we claim as new and desire tosecure by Letters-Patent, is

1. In stay bolt construction, the fombination of a bushing, a cap forthe same, a bolt engaging the bushing and a yielding member interposedbetween the head of the bolt and the cap.

2. In stay bolt construction, the combination of a bushing, a cap forthe same, a bolt engaging the bushing and a yielding member interposedbetween the head of the bolt and the cap and forming a steam tight elosure with the latter.

3. In stay bolt construction, the combination of a bushing, a boltVhaving a head seated on a sea-t in the bushing the said bolt having atell-tale bore, a cap for the bushing, the said cap having a hole inline with the tell tale bore in the bolt and a spring memberintermediate the head of the bolt and the cap, and having a central boreconnecting the tell-tale in the bolt with the hole in the cap.

4C. In stay bolt construction the combination of a bushing, a bolt thehead of which is seated in the bushing and is provided with a tell-talebore, a cap having a centrally located hole, and a spring memberinterposed between the head of the bolt and the cap and having a centralbore and steam tight contact with the bolt head and cap.

5. In stay bolt construction, the combination of a bushing, a cap forthesame, a bolt the head of which is seated inthe bushing, a yieldingmember interposed between the head of the bolt and the cap andanadjusting screw carried by the cap and bean ing on the spring member.

6. In stay bolt construction, the combination'of a bushing, a cap forthe same, a bolt communicating telltale bores. V

In testimony whereof, we have signed this specification 1n the presenceofv two subscribing witnesses.

BENJAMIN n. n. saumronn. ETHAN I. nonns.

iVitnesses:

EDWIN S. Bron, Howano j O. Caernn.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner o1' Patent.. Washington, D. C.

